When you think of growing bitcoin safely, you get very few possibilities. Also it needs long time to grow compared to the methods which involves high risk factors. Upon ones need can decide which method to be chosen for growing hard earned bitcoin.
Best way to grow your coins is just keep on earning from signature campaigns only and just keep on collecting it, and one day when you will have enough coins u will yourself know where to invest and how to start your own business with it...
yes. the only safe way to grow bitcoins is do things/work and get paid in bitcoins. like signature campaign. social marketing. link sharing. designing, writing. posting etc.
all of investments which require you to deposit or pay first to earn money are obvious ponzi scammers.